The OASIS membership recently voted to approve version 1.0 of the Security Assertion Markup Language (SAML) as an OASIS standard. SAML is "an XML-based framework for Web services that allows the exchange of authentication and authorization information among business partners. SAML enables Web-based security interoperability functions, such as single sign-on, across sites hosted by multiple companies. SAML incorporates industry-standard protocols and messaging frameworks, such as XML Signature, XML Encryption, and SOAP. The specification can be easily integrated in standard environments such as HTTP and standard Web browsers. Likewise, other security environments can use SAML as an authentication and authorization layer. SAML complements Web services standards, such as SOAP, which lack inherent security features. The OASIS Web Services Security Technical Committee, for example, is profiling SAML as one of its set of security tokens."

"SAML 1.0 is an important industry standard for federating diverse security domains across Web services environments," said James Kobielus, senior analyst at Burton Group. "SAML 1.0 supports secure interchange of authentication and authorization information by leveraging the core Web services standards of Extensible Markup Language (XML), Simple Object Access Protocol (SOAP), and Transport Layer Security (TLS). Most vendors of Web access management solutions have committed to SAML 1.0 and are currently implementing the specification in their products."

"SAML lets companies implement single sign-on solutions that allow users to visit various Web sites without being repeatedly challenged for credentials," explained Joe Pato of HP, co-chair of the OASIS Security Services Technical Committee. "In addition, SAML makes it possible to include security information in documents used in business transactions. This is particularly relevant for Web services, where security is critical."

"SAML allows vendors to interoperate for the benefit of their customers," said Jeff Hodges, Sun Microsystems, co-chair of the OASIS Security Services Technical Committee. "The standard is easily implemented by companies in existing environments, and SAML-aware security applications are already being introduced. Related security initiatives, such as Liberty Alliance's Version One Specification, are leveraging SAML in order to more quickly realize their goals."

The Security Assertion Markup Language (SAML) is "an XML-based framework for exchanging security information. This security information is expressed in the form of assertions about subjects, where a subject is an entity (either human or computer) that has an identity in some security domain. A typical example of a subject is a person, identified by his or her email address in a particular Internet DNS domain. Assertions can convey information about authentication acts performed by subjects, attributes of subjects, and authorization decisions about whether subjects are allowed to access certain resources. Assertions are represented as XML constructs and have a nested structure, whereby a single assertion might contain several different internal statements about authentication, authorization, and attributes. Note that assertions containing authentication statements merely describe acts of authentication that happened previously. Assertions are issued by SAML authorities, namely, authentication authorities, attribute authorities, and policy decision points.

SAML defines a protocol by which clients can request assertions from SAML authorities and get a response from them. This protocol, consisting of XML-based request and response message formats, can be bound to many different underlying communications and transport protocols; SAML currently defines one binding, to SOAP over HTTP. SAML authorities can use various sources of information, such as external policy stores and assertions that were received as input in requests, in creating their responses. Thus, while clients always consume assertions, SAML authorities can be both producers and consumers of assertions."